package com.xh3140.android.widget.sliderbar;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.MotionEvent;

import androidx.annotation.Nullable;

public class SliderBar extends AbstractSliderBar {
    // 值，必须在范围下限与上限之间
    private float mValue;

    // 激活状态，当用户按下滑块时，处于激活状态
    private boolean mActivated;

    // 触摸事件
    @Nullable
    private MotionEvent mMotionEvent;

    // 进度改变监听器
    @Nullable
    private OnValueChangedListener mOnValueChangedListener;

    public interface OnValueChangedListener {
        void onValueChanged(float value);
    }

    public SliderBar(Context context) {
        super(context);
    }

    public SliderBar(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public SliderBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public SliderBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 滑块坐标
        final float blockX = mSliderStripRectF.left + v2d(mValue - mRangeLower);
        // 绘制滑条(普通状态)
        mPaint.setColor(mSliderStripColor);
        canvas.save();
        canvas.clipRect(blockX, mSliderStripRectF.top, mSliderStripRectF.right, mSliderStripRectF.bottom);
        if (mSliderStripRadius > 0) {
            canvas.drawRoundRect(mSliderStripRectF, mSliderStripRadius, mSliderStripRadius, mPaint);
        } else {
            canvas.drawRect(mSliderStripRectF, mPaint);
        }
        canvas.restore();
        // 绘制滑条(覆盖状态)
        mPaint.setColor(mSliderBlockColor);
        canvas.save();
        canvas.clipRect(mSliderStripRectF.left, mSliderStripRectF.top, blockX, mSliderStripRectF.bottom);
        if (mSliderStripRadius > 0) {
            canvas.drawRoundRect(mSliderStripRectF, mSliderStripRadius, mSliderStripRadius, mPaint);
        } else {
            canvas.drawRect(mSliderStripRectF, mPaint);
        }
        canvas.restore();
        // 绘制滑块
        mPaint.setColor(mSliderBlockColor);
        if (mActivated) {
            canvas.drawCircle(blockX, mSliderBlockCenter, 1.5f * mSliderBlockRadius, mPaint);
        } else {
            canvas.drawCircle(blockX, mSliderBlockCenter, mSliderBlockRadius, mPaint);
        }
    }

    @Override
    public boolean performClick() {
        return super.performClick();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mActivated = true;
                final float distance = event.getX() - mSliderStripRectF.left;
                setValue(constraintInRange(mRangeLower + d2v(distance)));
                mMotionEvent = MotionEvent.obtain(event);
                invalidate();
                break;
            case MotionEvent.ACTION_MOVE:
                if (mMotionEvent != null) {
                    final float distance1 = event.getX() - mMotionEvent.getX();
                    if (distance1 == 0F) return false;
                    if (distance1 < 0F && mValue <= mRangeLower) return false;
                    if (distance1 > 0F && mValue >= mRangeUpper) return false;
                    setValue(constraintInRange(mValue + d2v(distance1)));
                    mMotionEvent = MotionEvent.obtain(event);
                    invalidate();
                }
                break;
            case MotionEvent.ACTION_UP:
                performClick();
                mActivated = false;
                if (mMotionEvent != null) {
                    mMotionEvent.recycle();
                    mMotionEvent = null;
                }
                invalidate();
                break;
        }
        return true;
    }

    /**
     * 获取值
     */
    public float getValue() {
        return mValue;
    }

    /**
     * 设置值
     *
     * @param value 值
     */
    public void setValue(float value) {
        if (mValue != value && mRangeLower <= value && mRangeUpper >= value) {
            mValue = value;
            if (mOnValueChangedListener != null) {
                mOnValueChangedListener.onValueChanged(mValue);
            }
            invalidate();
        }
    }

    /**
     * 设置值，悄悄的，不会引发监听器
     *
     * @param value 值
     */
    public void setValueQuietly(float value) {
        if (mValue != value && mRangeLower <= value && mRangeUpper >= value) {
            mValue = value;
            invalidate();
        }
    }

    /**
     * 设置值改变监听器
     *
     * @param listener 监听器
     */
    public void setOnValueChangedListener(@Nullable OnValueChangedListener listener) {
        mOnValueChangedListener = listener;
    }
}
